Retinol

* Vitamin A

* An active acne and anti-aging ingredient

* Please see TIA's post on Retinol: When to Use It, How to Use It

Functions:

Retinol is Vitamin A in its whole molecule form, which can be broken down into thousands of smaller components, including Retinoic Acid (or Tretinoin, the active ingredient in Renova and Retin-A). It belongs to the family of chemical compounds known as retinoids and is one of the most important vitamins for the appearance of the skin because of its small molecular structures. These tiny molecules have the ability to penetrate the outer layers of the skin and work to repair the lower layers where collagen and elastin reside, according to RetinolSkincare.org. Vitamin A is thought to renew and regenerate skin cells and stimulate new collagen production; to have antioxidant properties; and to serve as a skin exfoliator, unclogging pores and effectively treating and preventing acne.

Vitamin A itself does not have a direct effect on skin, but is only effective after specialized enzymes in the skin cells convert Vitamin A into Retinoic Acid (Tretinoin). Retinoic Acid facilitates communication between cells, encouraging aging cells to continue their renewal process and regenerate collagen and elastin to prevent the appearance of aging skin, wrinkles and fine lines. It is also effective at producing new, healthy skin cells to replace skin previously damaged by acne. However, Retinol cannot communicate with a cell until it has been broken down into Retinoic Acid (SmartSkinCare.com and RetinolSkincare.org). Once this breakdown has occurred, communication begins and the cells' turnover rate increases, increasing the production of collagen at a higher rate.

Retinol is considered a thorough exfoliator, and this repeated shedding of the upper dermal layer forces the skin to produce new cells. Although new cells are constantly created below the skin and enhanced by the communication and cell turnover facilitated by the Retinoic Acid, there is some concern that at the Hayflick Limit (the number of times skin can regenerate itself before reaching its limit, at 52 times), the aging process will actually be enhanced because cells are unable to multiple indefinitely.

Retinol is FDA and CIR approved for use.

Safety Measures/Side Effects:

Retinol is a controversial ingredient because of its potentially hazardous side effects. Although it has many proven benefits, the Cosmetics Database rates it as a moderate hazard ingredient. It warns of potential side effects including cancer, developmental and reproductive toxicity, violations, restrictions and warnings, cellular level changes and organ system toxicity. Retinol has been shown to produce excess reactive oxygen species that can interfere with cellular signaling, cause mutations, lead to cell death, and it may be implicated in cardiovascular disease. It has caused reproductive effects at low doses in one or more animal studies, and there is limited evidence of cancer and skin toxicity, although it has been shown to be easily absorbed into the skin.

Retinol (along with Tretinoin) can cause severe skin reactions, including peeling, redness, scaling, itching and burning. Formulas containing this ingredient, prescribed or OTC, are expected to cause some irritation upon use, although the irritation should decrease after approximately two weeks of continued application. It is also known to cause thinning of the skin, and therefore should not be used in conjunction with hair removal waxing (Wikipedia).

Retinol greatly increases the risk of extreme sunburn; care should be taken (shade, sunscreen, etc.) to protect treated skin from overexposure to ultraviolet light.

Recommended Products w/ Retinol:

Dermaradiant Ageless Eyes, Avene Retrinal - A Retinol for Sensitive Skins, Glo Therapeutics GloSuper Serum, Skin Doctors Retanew, GM Collin Retinol Advanced, YNS Cell Renewal, Biojuvenate Vitanol-A, Remergent Advanced Retinol Therapy, Replenix Retinol Plus Smoothing Serum 10X, SkinMedica Retinol Complex